ES2654178T3 - Data communication procedure between a roaming radio device and a network access gateway - Google Patents

Abstract

Data communication procedure between a radio communications equipment (101) intended to be integrated in a roaming carrier (P), and a gateway (103) connected to a network (R), the data being organized in the form of packets that they comprise at least a first network header called an internal header, which corresponds to a network link between a local communications equipment belonging to a local network (102) integrated on board said bearer (P) and an equipment (108) of remote communications connected to said network (R) and a second network header, called an external header, which corresponds to a network link between said radio communications equipment (101) and a personal agent (106), home agent, connected to the gateway (103) said process being characterized in that it comprises at least: - an initial phase of information exchange comprising: - the transmission (310) by the radio communications equipment to the gateway or receiving it n by the gateway from the radio communications equipment of at least one predictable field between the fields of the external header and the internal header, a predictable field being a header field whose value is fixed or constant regardless of the communication from, or destined for, the radio communications equipment (101), - the reception (410) by the radio communications equipment from the gateway or the transmission by the gateway to the radio communications equipment of at least one field predictable of the external header, - a transmission phase of at least one data packet comprising: - the deletion (302) of the external header and the internal header of said at least one data packet, - the generation (303), in said at least one data packet, of a lower level header to a network layer comprising at least one non-predictable field between the internal header fields, - the transmission (304) of said at least one data package

Description

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DESCRIPTION

Data communication procedure between a roaming radio device and a network access gateway

The invention relates to the field of communication systems in which a mobile mobile carrier is arranged to communicate with a telecommunications network. The communication system integrated in the roaming bearer is arranged to connect to the network through different network access gateways according to the position of the bearer. The invention thus relates to telecommunication networks in which mobility management is carried out at the network level. The invention finally relates to the field of optimization of the use of the bandwidth in the radio link between the mobile carrier and the network access gateway.

The invention is more precisely about a communication procedure between a roaming radio equipment and a network access gateway that allows optimization of the spectral resources consumed in this communication link.

Figure 1 represents an example of a communication system in which a mobile carrier P, for example an aircraft, communicates with a fixed infrastructure network R. Such a system is adapted for example to implement the ATN (Aeronautical Telecommunication Network) standard specified by the international civil aviation organization (ICAO).

The mobile carrier P includes at least one integrated radio communications equipment 101 that can be connected by itself to a local on-board network 102.

The mobile carrier P connects to the fixed infrastructure network R through an access gateway 103, 104, 105. This gateway establishes a radio link with the airborne communication equipment 101 according to a radio communications technology, for example a satellite communications link. The mobile carrier P connects to an access gateway 103, 104, 105 that is in its radio range. Thus, access to the network R can be made through different access gateways 103, 104, 105. Each access gateway is connected to an agent 106, 107 personal or home agent in English that is an entity of the R network whose role is the management of the mobility of the equipment that wishes to connect to the network through the gateways of access. Each radio communications equipment 101 is associated with a personal agent 106, 107. A personal agent 106 may be implemented on a device other than the access gateway 103 provided that it is connected to this gateway or implemented on the same equipment as the access gateway 103. The same personal agent 106 can be connected to several access gateways 103, 104, 105.

In the example of FIG. 1, a communication link between the integrated equipment 101 and a remote terminal 108 connected to the network R is considered as an illustration. The mobile carrier P moves from a first zone in the radio range of a first gateway 105 towards a second radio range zone of a second gateway 103.

In order to establish and maintain communication between the integrated equipment 101 and the remote terminal 108 regardless of the position of the mobile carrier P, two network links are established.

A first network link is established between the integrated equipment 101 and the remote terminal 108. The link is established from a permanent network address of the integrated device 101 and a permanent network address of the remote terminal 108.

In order to manage the mobility of the bearer P, a second network link is established in tunnel mode between a provisional network address of the integrated equipment 101, which belongs to the same network as the access gateway, and the network address of the 106 staff agent in charge of mobility management. The provisional network address is assigned by the network access gateway.

This mobility management mechanism makes it possible to avoid the implementation of complex routing mechanisms when the carrier P changes the access gateway in the course of its movement.

However, the use of two network links, of which one is through a tunnel, for the same point-to-point communication implies inconveniences. A transmitted data packet includes two network headers whose size is significant, particularly for networks that use the IPv6 protocol. An IPv6 header has a size of 40 octets. However, the radio link between the mobile carrier P and the network access gateway is very often a reduced bandwidth link available, in particular in the case of the aeronautical communication link. The use of two IPv6 headers to establish a communication link implies a non-optimal use of the resources available in the radio channel because the introduction of two network headers in each transmitted packet decreases the bandwidth available for the data to the same extent transmitted tools.

A known solution that optimizes radio resources in the case of transmissions based on the IP network protocol is to use a network header compression mechanism, such as the RoHC (Robust Header Compression) mechanism standardized by the IETF body under reference RFC3095.

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For example, US Patent Application US2004 / 001508 discloses a method based on a header compression mechanism.

This mechanism makes it possible to reduce the size of the network header but has other drawbacks. You need an initial phase of prior guest relationship for each exchange session and it is complex to implement. In addition, it also requires the maintenance of synchronization between the contexts stored for each guest to be able to correctly operate the decompression of the headers and is therefore sensitive to any phenomenon of desynchronization.

The invention proposes a transmission procedure between a radio equipment integrated in a mobile carrier and an access gateway to a fixed network that allows optimizing the available bandwidth resources.

The solution proposed by the invention consists in suppressing in the broadcast the predictable fields of the network headers and in reconstructing in the reception the deleted headers.

The object of the invention is two methods of data communication between a radio communications equipment intended to be integrated in a roaming carrier, and a gateway connected to a network, the data being organized in the form of packets comprising at least a first network header called internal header, which corresponds to a network link between a local communications equipment belonging to a local network integrated on board said bearer and a remote communication equipment connected to said network and a second network header, called external header, which corresponds to a network link between said radio communications equipment and a personal agent connected to the gateway, according to independent claims 1 and 2.

A subject of the invention is a computer program according to independent claim 8.

A subject of the invention is still a radio communications equipment according to independent claim 9.

A subject of the invention is still a network gateway according to independent claim 10.

Other features and advantages of the present invention will emerge better by reading the following description in relation to the accompanying drawings that represent:

- Figure 1, a synoptic of a telecommunications network in which a mobile carrier can connect to the fixed infrastructure network,

- Figure 2, a scheme illustrating the protocol implementation of a communication link in the network of Figure 1,

- Figure 3, an organization chart illustrating the method of data transmission according to the invention.

Figure 2 schematically illustrates the mechanisms implemented during a transmission between the integrated communications equipment 101 and a remote terminal 108 connected to the R network.

The R network uses a protocol architecture based on a model of the type comprising at least four layers: an application AP layer, a network IP layer, a data link LD layer and the physical PHY layer. The protocol architecture model is mainly inspired by the ISO (Open Systems Interconnection) model also known under the English acronym OSI (Open Systems Interconnection) comprising seven layers.

Figure 2 shows a transmission initiated by the integrated device 101 destined for the remote terminal 108. The transmission mechanism put into play for a communication from the remote terminal 108 towards the integrated equipment 101 is similar.

A data packet P10 is generated in the application layer of the integrated device 101 or of a device connected to the local network integrated in the mobile carrier P. The generated P10 packet is transmitted to the network IP layer to be encapsulated twice successively in a network packet. To this end, a first internal network header is added which mainly comprises the permanent network address of the source radio equipment 101 and the permanent network address of the remote destination terminal 108. A second network header is also added to establish the network link in tunnel mode between radio equipment 101 and personal agent 106. The second external network header comprises a provisional network address of the radio equipment 101, assigned by the gateway 103, and the permanent network address of the personal agent 106. The internal network header and the external network header are for example IPv6 headers.

The network packet P11 thus constructed is transmitted to the data link layer which also adds a specific header to generate a new packet P12 that is transmitted to the physical layer and subsequently transmitted via radio to the gateway 103.

Gateway 103 decapsulates the received P32 packet to the level of the network IP layer. At this level, the gateway 103 transmits the network packet P @ 1 to the personal agent 106 that suppresses the external network header and communicates the network packet P60 to the destination terminal 108 that retrieves the application Pbq packet.

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The use of a second IP tunnel between the radio equipment 101 and the personal agent 108 allows the management of the mobility of the bearer P that can be connected to different network access gateways. The personal agent 106 is unique to each bearer P which allows to effectively manage the routing of the packets to their destination regardless of the position of the bearer P.

As indicated in the preamble, the addition of two network headers to each packet generates excess bandwidth consumption of the radio link between the carrier P and the gateway 103 to the detriment of the speed assigned to the useful data.

The invention proposes a mechanism that solves this problem.

Figure 3 illustrates the data transmission method according to the invention.

The procedure includes a first initial phase of information exchange between the integrated radio equipment 101 and the gateway 103 and subsequently a second phase of data transmission.

The first phase of information exchange takes place when the bearer P wishes to register in the network R before the gateway 103 which is the closest and in radio range.

The radio equipment 101 identifies a priori, in the two network headers of the packets to be transmitted, the predictable fields throughout the transmission from, or destined for, the radio equipment 101 or in the local network integrated in the bearer Q. A predictable field is understood in this case as a header field whose value is fixed or constant regardless of the communication coming from, or destined for, the radio equipment 101.

In the internal network header, a predictable field is the permanent address field of the radio equipment 101 or the prefix of this permanent address in case its suffix is used to assign permanent network addresses to different equipment connected in the within a local network integrated in the bearer P. The address of the remote terminal 108 is generally not predictable since it is not known, a priori, with which terminal the radio equipment 101 can be arranged to communicate. It can however be equally predictable in the particular case in which the carrier P systematically communicates with the same remote terminal.

In the external network header, a predictable field is the address field of the personal agent 106. Indeed, there is a unique pairing between each itinerant carrier P and a personal agent in charge of managing the mobility of this carrier in the R network.

The provisional network address of the radio equipment 101, also included in the external network header, is assigned by the access gateway 103 and is therefore equally predictable because all communications involving the radio equipment 101 will use this provisional address.

In a particular embodiment of the invention, only a prefix of the provisional network address is assigned by the access gateway. The suffix of the provisional network address is determined from the prefix and its own identifier for radio equipment 101, for example an identifier of the type EUI-64. The access gateway transmits the suffix to the radio equipment which can then generate the entire provisional network address from the identifier.

In summary, in the initial phase of exchanges of the method according to the invention, the radio equipment 101 identifies 301 the predictable fields of which it has knowledge in the two network headers and subsequently transmits them to the gateway 103. Similarly, the gateway 103 It identifies 401 the predictable fields of which it has knowledge and transmits them to radio equipment 101.

As a result of this initial phase, the two entities 101, 103 relevant parties in the radio link each have a local copy of the predictable fields of the two network headers.

In a second phase of data transmission, a data packet P11, coming from the network layer, is intercepted at the level of the data link layer LD. The two network headers are deleted 302. A link header is added to the packet 303. It comprises the unpredictable fields of the two network headers. For example, it comprises the destination address of the remote terminal 108. It may also comprise the suffix of the permanent network address of the radio equipment 101 when this suffix is used to assign several permanent addresses to some equipment located on board the carrier P, in other words when several devices are addressable on board the carrier in the sine of the prefix assigned during the registration of the bearer before the gateway.

The packet comprising the link header generated according to the invention is then transmitted 304 to the physical layer and subsequently transmitted by radio to the gateway 103.

Upon receipt of the packet, the following processing is performed by the gateway at the level of the data link layer LD. 404 the internal network header is rebuilt from the unpredictable fields contained in the link header and the predictable fields exchanged during the initial phase. The external network header is rebuilt 403 from the predictable fields exchanged during the initial phase. Then, the link header is deleted 402.

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The transmission mechanism according to the invention is described in Figure 2 in a non-limiting example for which communication is initiated by the integrated equipment 101 towards the remote terminal 108. But the transmission can also be done in the opposite direction. In the latter case, the processing performed respectively by the radio equipment 101 and the gateway 103 is reversed.

Without leaving the scope of the invention, the transmission method according to the invention can also be implemented at the level of the physical layer or of any abstraction layer located at a level lower than the network layer.

The invention is advantageously applied when associated with the IPv6 protocol because in this case it allows a significant gain over the economized transmission resources due to the suppression of IPv6 headers. But the invention also applies to the IPv4 protocol, as well as to any network protocol that allows the unique addressing of the hosts within the network.

During the reconstruction phase of the network headers, the header fields other than the source address and the destination address can be reconstructed from the fields contained in the link header or from default values or even from values exchanged during the initial phase of exchanges.

The method according to the invention can be implemented from material and / or software elements. It can be implemented mainly as a computer program that includes instructions for its execution. The computer program can be registered in a registration medium readable by a processor. The support can be electronic, magnetic, optical or electromagnetic.

In particular, the invention can be implemented by a device comprising a processor and a memory. The processor can be a generic processor, a specific processor, a specific application integrated circuit (also known under the English name of ASIC by "Application-Specific Integrated Circuit") or an array of field-programmable gates (also known under the name FPGA English for “Field-Programmable Gate Array”).

The device may use one or more dedicated electronic circuits or a general purpose circuit. The technique of the invention can be carried out in a reprogrammable calculation machine (a processor or microcontroller for example) that executes a program comprising a sequence of instructions, or in a dedicated calculation machine (for example a set of logic gates such as a FPGA or an ASIC, or any other material module).

According to one embodiment, the device comprises at least one computer-readable storage medium (RAM, ROM, EEPROM, flash memory or any other memory technology, CD-ROM, DVD or any other optical disk media, magnetic cassette, magnetic stripe, magnetic storage disk or other storage device, or other non-transient computer readable storage media) encoded with a computer program (i.e. several executable instructions) that, when executed on a processor or multiple processors, performs the functions of the embodiments of the invention described above.

The invention can be implemented in radio communications equipment 101 integrated in the roaming bearer and in the network access gateway 103. The invention is implemented at the level of the data link layer or of any abstraction layer located at a level lower than the network layer.

By way of example of a material architecture adapted to implement the invention, a device according to the invention can include a communication bus to which a central processing unit or microprocessor (CPU), an acronym for "Central Processing Unit" in English, is connected. non-volatile memory (ROM, acronym for "Read Only Memory" in English) that may include the programs necessary for the implementation of the invention, a volatile memory or cache (RAM), which includes "Random Access Memory 'in English" which includes records adapted to record variables and parameters created and modified during the execution of the aforementioned programs, and a communication or I / O interface (acronym I / O acronym for “Input / output” in English) adapted to transmit and to receive data.

The reference to a computer program that, when executed, performs any of the functions described above, is not limited to an application program that runs on a single host computer. On the contrary, the terms computer program and software will be used in this case in a general sense to refer to any type of computer code (for example, an application software, a micro-software, a micro-code, or any another form of computer instruction) that can be used to program one or more processors to implement aspects of the techniques described in this document. The media or computing resources can be mainly distributed (“Cloud computing”), possibly according to peer technologies. The software code can be executed in no matter which appropriate processor (for example, a microprocessor) or processor core or set of processors, whether they are provided in a single calculation device or distributed among several calculation devices (for example such as eventually accessible in the device environment). The executable code of each program that allows the

Programmable device implementing the processes according to the invention, may be stored, for example, on the hard disk or in non-volatile memory. In general, the program (s) may be loaded into one of the storage media of the device before running. The central unit can control and direct the execution of the instructions or parts of the software code of the program or programs according to the invention, instructions that are stored in the hard disk or in the non-volatile memory or in the other storage elements before mentioned.

The invention has the advantage of saving the signaling data transmitted on the radio link in favor of the possible increase in the speed of the useful data.

In particular, when the invention is applied to the IPv6 protocol, the gain contributed by the suppression of the two 10 network headers varies from 56 to 64 octets, even 80 octets in certain cases.

Another advantage linked to the invention is that the suppression of the predictable fields of the headers of each packet transmitted on the radio link allows these fields to be impacted by transmission errors linked to the propagation channel.

Claims (10)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 1. Data communication procedure between a radio communications equipment (101) intended to be integrated in a roaming carrier (P), and a gateway (103) connected to a network (R), the data being organized in the form of packets comprising at least a first network header called an internal header, which corresponds to a network link between a local communications equipment belonging to a local network (102) integrated on board said carrier (P) and a device (108 ) of remote communications connected to said network (R) and a second network header, called an external header, which corresponds to a network link between said radio communications equipment (101) and a personal agent (106), home agent, connected to the gateway (103) said process being characterized in that it comprises at least: - an initial phase of information exchange comprising: > the transmission (310) by the radio communications equipment to the gateway or the reception by the gateway from the radio communications equipment of at least one predictable field between the external header and internal header fields, being a predictable field a header field whose value is fixed or constant regardless of the communication coming from, or destined for, the radio communications equipment (101), > the reception (410) by the radio communications equipment from the gateway or the transmission by the gateway to the radio communications equipment of at least one predictable field of the external header, - a transmission phase of at least one data packet comprising: > the deletion (302) of the external header and the internal header of said at least one data packet, > the generation (303), in said at least one data packet, of a lower level header to a network layer comprising at least one non-predictable field between the internal header fields, > the transmission (304) of said at least one data packet. 2. Data communication procedure between a radio communications equipment (101) intended to be integrated in a roaming carrier (P), and a gateway (103) connected to a network (R), the data being organized in the form of packets comprising at least a first network header called an internal header, which corresponds to a network link between a local communications equipment belonging to a local network (102) integrated on board said carrier (P) and a device (108 ) of remote communications connected to said network (R) and a second network header, called an external header, which corresponds to a network link between said radio communications equipment (101) and a personal agent (106), home agent, connected to the gateway (103) said process being characterized in that it comprises at least: - an initial phase of information exchange comprising: > the transmission (310) by the radio communications equipment to the gateway or the reception by the gateway from the radio communications equipment of at least one predictable field between the external header and internal header fields, being a predictable field a header field whose value is fixed or constant regardless of the communication coming from, or destined for, the radio communications equipment (101), > the reception (410) by the radio communications equipment from the gateway or the transmission by the gateway to the radio communications equipment of at least one predictable field of the external header, - a data reception phase comprising: > receiving (304) of at least one data packet comprising a lower level header than a network layer > the reconstruction (404), in the data packet, of an internal network header at least from at least one predictable field transmitted during the initial phase and of at least one unpredictable field comprised in the lower level header a network layer of said data packet, said internal network header corresponding to a network link between a local communications equipment belonging to a local network integrated on board said bearer and a remote communications equipment connected to said network, > the reconstruction (403), in the data packet, of an external network header at least from at least one predictable field transmitted during the initial phase, said external network header corresponding to a network link between said equipment of radio communications and said personal agent, home agent, connected to the gateway, > the deletion (402) of the lower level header to a network layer in said data packet. 3. Data communication method according to one of the preceding claims wherein the predictable fields of the internal header comprise at least one prefix of the permanent network address of the equipment 5 10 fifteen twenty 25 30 of radio communications. 4. A data communication method according to one of the preceding claims wherein the non-predictable fields of the internal header comprise at least the network address of the remote communications equipment connected to said network. 5. The data communication method according to claim 4 wherein the non-predictable fields of the internal header comprise the suffix of the permanent network address of the radio communications equipment. 6. A data communication method according to one of the preceding claims wherein the predictable fields of the external header comprise at least a part of the provisional network address of the radio communications equipment assigned by the gateway and the agent's network address. personal, home agent. 7. Data communication method according to claim 5 wherein: - the provisional network address of the radio communications equipment is composed of a prefix assigned by the gateway and a suffix generated from an identifier of the radio communications equipment itself, - the initial phase of information exchange includes: > the transmission by the radio communications equipment to the gateway or the reception by the gateway from the radio communications equipment of said identifier, > the reception by the radio communications equipment from the gateway or the transmission by the gateway to the radio communications equipment of said prefix assigned by the gateway. 8. Computer program that includes instructions for the execution of the data transmission procedure and / or the data reception procedure according to one of the preceding claims, when the program is executed by a processor. 9. Radio communications equipment (101) intended to be integrated in a roaming carrier (P) comprising suitable communication means to respect a network architecture according to a layered model comprising at least one network layer and one layer of connection, said communication means being configured to execute the data communication method according to one of claims 1 to 7. 10. Network gateway (103) intended to connect to a network (R) through a personal agent (106), home agent, of the network and comprising adequate communication means to respect a network architecture according to a model in layers comprising at least one network layer and one link layer, said communication means being configured to execute the data communication method according to one of claims 1 to 7.